/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

#include <AudioUnit/AudioUnit.h>

#include "SDL_audio.h"

#include "../SDL_audio_c.h"

#include "../SDL_sysaudio.h"

#include "SDL_coreaudio.h"

/* Audio driver functions */

static int Core_OpenAudio(_THIS, SDL_AudioSpec *spec);

static void Core_WaitAudio(_THIS);

static void Core_PlayAudio(_THIS);

static Uint8 *Core_GetAudioBuf(_THIS);

static void Core_CloseAudio(_THIS);

/* Audio driver bootstrap functions */

static int Audio_Available(void)

{

    return(1);

}

static void Audio_DeleteDevice(SDL_AudioDevice *device)

{

    SDL_free(device->hidden);

    SDL_free(device);

}

static SDL_AudioDevice *Audio_CreateDevice(int devindex)

{

    SDL_AudioDevice *this;

    /* Initialize all variables that we clean on shutdown */

    this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));

    if ( this ) {

        SDL_memset(this, 0, (sizeof *this));

        this->hidden = (struct SDL_PrivateAudioData *)

                SDL_malloc((sizeof *this->hidden));

    }

    if ( (this == NULL) || (this->hidden == NULL) ) {

        SDL_OutOfMemory();

        if ( this ) {

            SDL_free(this);

        }

        return(0);

    }

    SDL_memset(this->hidden, 0, (sizeof *this->hidden));

    /* Set the function pointers */

    this->OpenAudio = Core_OpenAudio;

    this->WaitAudio = Core_WaitAudio;

    this->PlayAudio = Core_PlayAudio;

    this->GetAudioBuf = Core_GetAudioBuf;

    this->CloseAudio = Core_CloseAudio;

    this->free = Audio_DeleteDevice;

    return this;

}

AudioBootStrap COREAUDIO_bootstrap = {

    "coreaudio", "Mac OS X CoreAudio",

    Audio_Available, Audio_CreateDevice

};

/* The CoreAudio callback */

static OSStatus     audioCallback (void                             *inRefCon, 

                                    AudioUnitRenderActionFlags      inActionFlags,

                                    const AudioTimeStamp            *inTimeStamp, 

                                    UInt32                          inBusNumber, 

                                    AudioBuffer                     *ioData)

{

    SDL_AudioDevice *this = (SDL_AudioDevice *)inRefCon;

    UInt32 remaining, len;

    void *ptr;

    /* Only do anything if audio is enabled and not paused */

    if ( ! this->enabled || this->paused ) {

        SDL_memset(ioData->mData, this->spec.silence, ioData->mDataByteSize);

        return 0;

    }

    /* No SDL conversion should be needed here, ever, since we accept

       any input format in OpenAudio, and leave the conversion to CoreAudio.

     */

    /*

    assert(!this->convert.needed);

    assert(this->spec.channels == ioData->mNumberChannels);

     */

    remaining = ioData->mDataByteSize;

    ptr = ioData->mData;

    while (remaining > 0) {

        if (bufferOffset >= bufferSize) {

            /* Generate the data */

            SDL_memset(buffer, this->spec.silence, bufferSize);

            SDL_mutexP(this->mixer_lock);

            (*this->spec.callback)(this->spec.userdata,

                        buffer, bufferSize);

            SDL_mutexV(this->mixer_lock);

            bufferOffset = 0;

        }

        len = bufferSize - bufferOffset;

        if (len > remaining)

            len = remaining;

        SDL_memcpy(ptr, (char *)buffer + bufferOffset, len);

        ptr = (char *)ptr + len;

        remaining -= len;

        bufferOffset += len;

    }

    return 0;

}

/* Dummy functions -- we don't use thread-based audio */

void Core_WaitAudio(_THIS)

{

    return;

}

void Core_PlayAudio(_THIS)

{

    return;

}

Uint8 *Core_GetAudioBuf(_THIS)

{

    return(NULL);

}

void Core_CloseAudio(_THIS)

{

    OSStatus result;

    struct AudioUnitInputCallback callback;

    /* stop processing the audio unit */

    result = AudioOutputUnitStop (outputAudioUnit);

    if (result != noErr) {

        SDL_SetError("Core_CloseAudio: AudioOutputUnitStop");

        return;

    }

    /* Remove the input callback */

    callback.inputProc = 0;

    callback.inputProcRefCon = 0;

    result = AudioUnitSetProperty (outputAudioUnit, 

                        kAudioUnitProperty_SetInputCallback, 

                        kAudioUnitScope_Input, 

                        0,

                        &callback, 

                        sizeof(callback));

    if (result != noErr) {

        SDL_SetError("Core_CloseAudio: AudioUnitSetProperty (kAudioUnitProperty_SetInputCallback)");

        return;

    }

    result = CloseComponent(outputAudioUnit);

    if (result != noErr) {

        SDL_SetError("Core_CloseAudio: CloseComponent");

        return;

    }

    SDL_free(buffer);

}

#define CHECK_RESULT(msg) \

    if (result != noErr) { \

        SDL_SetError("Failed to start CoreAudio: " msg); \

        return -1; \

    }

int Core_OpenAudio(_THIS, SDL_AudioSpec *spec)

{

    OSStatus result = noErr;

    Component comp;

    ComponentDescription desc;

    struct AudioUnitInputCallback callback;

    AudioStreamBasicDescription requestedDesc;

    /* Setup a AudioStreamBasicDescription with the requested format */

    requestedDesc.mFormatID = kAudioFormatLinearPCM;

    requestedDesc.mFormatFlags = kLinearPCMFormatFlagIsPacked;

    requestedDesc.mChannelsPerFrame = spec->channels;

    requestedDesc.mSampleRate = spec->freq;

    requestedDesc.mBitsPerChannel = spec->format & 0xFF;

    if (spec->format & 0x8000)

        requestedDesc.mFormatFlags |= kLinearPCMFormatFlagIsSignedInteger;

    if (spec->format & 0x1000)

        requestedDesc.mFormatFlags |= kLinearPCMFormatFlagIsBigEndian;

    requestedDesc.mFramesPerPacket = 1;

    requestedDesc.mBytesPerFrame = requestedDesc.mBitsPerChannel * requestedDesc.mChannelsPerFrame / 8;

    requestedDesc.mBytesPerPacket = requestedDesc.mBytesPerFrame * requestedDesc.mFramesPerPacket;

    /* Locate the default output audio unit */

    desc.componentType = kAudioUnitComponentType;

    desc.componentSubType = kAudioUnitSubType_Output;

    desc.componentManufacturer = kAudioUnitID_DefaultOutput;

    desc.componentFlags = 0;

    desc.componentFlagsMask = 0;

    comp = FindNextComponent (NULL, &desc);

    if (comp == NULL) {

        SDL_SetError ("Failed to start CoreAudio: FindNextComponent returned NULL");

        return -1;

    }

    /* Open & initialize the default output audio unit */

    result = OpenAComponent (comp, &outputAudioUnit);

    CHECK_RESULT("OpenAComponent")

    result = AudioUnitInitialize (outputAudioUnit);

    CHECK_RESULT("AudioUnitInitialize")

    /* Set the input format of the audio unit. */

    result = AudioUnitSetProperty (outputAudioUnit,

                               kAudioUnitProperty_StreamFormat,

                               kAudioUnitScope_Input,

                               0,

                               &requestedDesc,

                               sizeof (requestedDesc));

    CHECK_RESULT("AudioUnitSetProperty (kAudioUnitProperty_StreamFormat)")

    /* Set the audio callback */

    callback.inputProc = audioCallback;

    callback.inputProcRefCon = this;

    result = AudioUnitSetProperty (outputAudioUnit, 

                        kAudioUnitProperty_SetInputCallback, 

                        kAudioUnitScope_Input, 

                        0,

                        &callback, 

                        sizeof(callback));

    CHECK_RESULT("AudioUnitSetProperty (kAudioUnitProperty_SetInputCallback)")

    /* Calculate the final parameters for this audio specification */

    SDL_CalculateAudioSpec(spec);

    /* Allocate a sample buffer */

    bufferOffset = bufferSize = this->spec.size;

    buffer = SDL_malloc(bufferSize);

    /* Finally, start processing of the audio unit */

    result = AudioOutputUnitStart (outputAudioUnit);

    CHECK_RESULT("AudioOutputUnitStart")    

    /* We're running! */

    return(1);

}